1. Field of the Invention
The present invention relates generally to a route selecting method, a route selecting system, and a recording medium, and more particularly, to a method used for a car navigation system for automatically selecting an optimum route between a departure point and a destination point which are designated on a map, a system using the method, and a medium having a program for carrying out the method recorded thereon.
2. Description of the Background Art
In recent years, navigation systems for guiding vehicles have rapidly started to spread as electronic techniques have been developed. The navigation systems include one comprising a route selecting system for automatically selecting an optimum route from a departure point to a destination point (for example, a shortest distance arrival route or a minimum time arrival route) in order to improve the driving convenience of a user. The conventional route selecting system will be simply described.
In the conventional route selecting system, an example of a method of finding an optimum route for guiding a vehicle is a method disclosed in Japanese Patent Laid-Open Publication No. 59-105113 (1984-105113) entitled xe2x80x9cMethod of Automatically Guiding Vehiclexe2x80x9d (hereinafter referred to as a first conventional method). The first conventional method is for finding an optimum route between a departure point and a destination point from data representing a network of roads by using a Dijkstra method, or the like, which is one of optimum route determining methods. The theory of the Dijkstra method is described in xe2x80x9cData Structure and Algorithmxe2x80x9d (BAIFUKAN CO., LTD, issued in 1990, pp. 179 to pp. 183) written by A. V. Eiho et al. and translated by Ono, for example.
In contrast with the above-mentioned first conventional method, an example of a method of finding an optimum route to which travel experience of a user is added is a method disclosed in Japanese Patent Laid-Open Publication No 8-20108(996-201088) entitled xe2x80x9cOn-vehicle Navigation Device having Route Searching Functionxe2x80x9d (hereinafter referred to as a second conventional method). In the second conventional method, an evaluation value of a road on which a user travels is changed depending on the frequency of travel and is stored. A road having a small evaluation value is selected in preference when a route is searched for the next time.
Another example of a method of finding an optimum route to which another opinion of a user is added is a method disclosed in Japanese Patent Laid-Open Publication No. 11-64030 (1999-64030) entitled xe2x80x9cNavigation Devicexe2x80x9d (hereinafter referred to as a third conventional method). In the third conventional method, a correction made by a user is reflected on an optimum route found by searching based on a departure point to a destination point is stored, and the route reflecting the correction is presented as a shortest route when the route from the same departure point to the same destination point is searched for again.
In a case where the evaluation value of the road on which the user travels is changed, as in the conventional second method, when a route different from the route at the time of changing the evaluation value (a route which differs in a departure point and/or a destination point) is searched for, a route forcedly using a road having an experience of travel (having a small evaluation value) may, in some cases, be selected.
In a case where the route reflecting the user correction is stored, as in the third conventional method, even for route searching that may utilize such user-corrected route, if a departure point and/or a destination point differs from that of the user-corrected route, a route which does not reflect the user-correction may be selected.
Therefore, an object of the present invention is to provide a route selecting method capable of selecting a route in which a road on which a user has traveled is suitably reflected, a system using the method, and a recording medium having a program for executing the method recorded thereon.
The present invention has the following features to solve the problem above.
A first aspect of the present invention is directed to a route selecting method for selecting an optimum route on a map in the travel of a vehicle. The route selecting method comprises searching for an optimum route between two points using map data required to select a route, collecting traveling tracks on which the vehicle travels, comparing the optimum route searched for and the traveling tracks collected, to store only different route parts on the traveling tracks as section traveling routes, when a user is guided, comparing the optimum route searched for and all the section traveling routes stored, to examine whether the section traveling route crossing the optimum route (hereinafter referred to as a crossing section traveling route) exists, replacing, with respect to the crossing section traveling route examined, a section on the optimum route which crosses the crossing section traveling route with a corresponding part of the crossing section traveling route, to generate a guiding route, and guiding the user using the guiding route generated.
As described above, in the first aspect, the section traveling route is stored only in the section in which the vehicle travels upon deviating from the optimum route is stored, and the user is guided, when the optimum route capable of using the section is searched for the next time, on a route obtained by replacing the route in the section with the stored section traveling route. Consequently, a route in which a road on which the user once traveled is suitably reflected is found depending on current circumstances, thereby making it possible to guide the user.
Preferably, the guiding step comprises displaying, when the guiding route is displayed, the optimum route together with the guiding route in such a manner that they can be distinguished.
Both the guiding route including the route on which the user once traveled and the optimum route in calculation are thus displayed, thereby making it possible for the user to refer to not only the guiding route, but also the optimum route.
Preferably, the storing step comprises deleting, with respect to the section traveling route already stored (hereinafter referred to as existing section traveling route), the existing section traveling route when the vehicle newly travels on a different route in the same section (from the same start point to the same end point) as and different from the existing section traveling route.
Accordingly, when the vehicle travels on a new route different from the existing section traveling route (the section traveling route on which the vehicle once traveled), data representing the existing section traveling route is deleted, thereby making it possible for the route on which the-vehicle once traveled, but has not recently traveled, not to be reflected in the guiding route.
Preferably, the storing step comprises accumulatively storing the number of times the vehicle travels on the section traveling route together with the section traveling route, and the generating step comprises using, for the replacement, only the crossing section traveling route on which the vehicle travels not less than a particular number of times.
The number of times the vehicle travels on the section traveling route and the section traveling route are thus recorded together, and the section traveling route is reflected in the guiding route only when the vehicle travels the section traveling route not less than a particular number of times, thereby making it possible to prevent the route or the like at which the vehicle accidentally uses from being reflected in the guiding route.
Preferably, the storing step comprises reducing, with respect to the existing section traveling route, the number of times the vehicle travels on the existing section traveling route when the vehicle newly travels on a different route in the same section as the existing section traveling route.
Accordingly, when the vehicle thus travels on a new route different from the existing section traveling route, the number of times the vehicle travels on the existing section traveling route is reduced, thereby making it possible to preferentially reflect the section traveling route which is high in the frequency of utilization in the guiding route.
Preferably, the route selecting method further comprises examining whether the section traveling route including a current position of the vehicle and having a point crossing the guiding route in the travel direction is stored on the basis of the traveling tracks collected and the guiding route generated, and generating, when the section traveling route exists, a new guiding route from the current position to a destination point using the section traveling route and the guiding route. The guiding step comprises guiding the user using the new guiding route generated when it is determined that the current position of the vehicle deviates from the guiding route.
Accordingly, when the current position thus deviates from the guiding route, the route to the destination point is newly generated on the basis of the route on which the vehicle has once traveled, thereby making it possible to guide a return route using the route on which the user has experience traveling. Accordingly, it is possible to enhance a user peace of mind.
Preferably, the storing step comprises storing circumstances where the vehicle travels on the section traveling route together with the section traveling route, and the generating step comprises using, for the replacement, only the crossing section traveling route whose circumstances stored at the storing step conform to the current circumstances.
The circumstances where the vehicle travels on the section traveling route and the section of the section traveling route are thus stored together, and only the section traveling route conforming to the current circumstances is reflected in the guiding route, thereby making it possible to select the optimum route depending on the circumstances.
Preferably, the route selecting method comprises inputting a route (a traveling track) on a map on which a user desires to travel, the storing step comprising finding the section traveling route using the traveling track inputted at the inputting step in place of the traveling tracks collected at the collecting step.
Accordingly, the route (the traveling track) desired by the user is inputted, and the section traveling route in the section different from the optimum route is stored using the route, thereby making it possible to reflect the route conforming to the desire of the user in the guiding route even if the user does not actually travel.
Preferably, the storing step comprises individually storing the section traveling route for each user, and the examining step and the generating step each comprise performing processing using only the section traveling route corresponding to the user. Consequently, it is possible to guide via an optimum route corresponding to an actual driver.
Preferably, the storing step comprises determining the section traveling route to be stored in accordance with judgment given from the user. Consequently, it is possible to guide via a more optimum route in which the intention of a driver is reflected.
A second aspect of the present invention is directed to a route selecting system for selecting an optimum route on a map in the travel of a vehicle. The route selecting system comprises a map data storage portion for storing map data required to select a route, a current position and traveling track detection portion for finding a current position and a traveling track of the vehicle, an information input portion for inputting particular information (a destination point and a departure point of a route, a current time zone and day of the week, an expected time zone and day of the week of departure/arrival, and the like) in accordance with an instruction issued by a user, an optimum route searching portion for searching for an optimum route between two points using the map data and the particular information, a section traveling route generation portion for comparing the optimum route searched for by the optimum route searching portion and the traveling track found in the current position and traveling track detection portion, to extract only different route parts on the traveling track as section traveling routes, and a section traveling route storage portion for storing the section traveling routes. The route selecting system further comprises a crossing section examination portion for, when the user is guided, comparing the optimum route searched for by the optimum route searching portion and all of the section traveling routes stored in the section traveling route storage portion, to examine whether the crossing section traveling route exists, a guiding route generation portion for replacing, with respect to the crossing section traveling route examined by the crossing section examination portion, a section on the optimum route which crosses the crossing section traveling route with a corresponding part of the crossing section traveling route, to generate a guiding route, and a map display output portion for guiding the user using the guiding route generated by the guiding route generation portion.
As described above, in the second aspect, the section traveling route is stored only in the section in which the vehicle travels upon deviating from the optimum route, and the user is guided, when the optimum route capable of using the section is searched for the next time, on a route obtained by replacing the route in the section with the stored section traveling route. Consequently, a route in which a road on which the user once traveled is suitably reflected is found depending on current circumstances, thereby making it possible to guide the user.
Preferably, the map display output portion displays, when the guiding route is displayed, the optimum route together with the guiding route in such a manner that they can be distinguished.
Accordingly, both the guiding route including the route on which the user once traveled and the optimum route in calculation are displayed, thereby making it possible for the user to refer to not only the guiding route, but also the optimum route.
Preferably, the section traveling route generation portion deletes, with respect to the existing section traveling route, the existing section traveling route when the vehicle newly travels on a different route in the same section as the existing section traveling route.
Accordingly, when the vehicle thus travels on a new route different from the existing section traveling route (the section traveling route on which the vehicle once traveled), data representing the existing section traveling route is deleted, thereby making it possible for the route on which the vehicle once traveled, but has not recently traveled, not to be reflected in the guiding route.
Preferably, the section traveling route storage portion accumulatively stores the number of times the vehicle travels on the section traveling route together with the section traveling route, and the guiding route generation portion uses, for the replacement, only the crossing section traveling route on which the vehicle travels not less than a predetermined number of times.
The number of times the vehicle travels on the section traveling route and the section traveling route are thus recorded together, and the section traveling route is reflected in the guiding route only when the vehicle travels the section traveling route not less than a particular number of times, thereby making it possible to prevent the route or the like at which the vehicle accidentally uses from being reflected in the guiding route.
Preferably, the section traveling route generation portion reduces, with respect to the existing section traveling route, the number of times the vehicle travels on the existing section traveling route when the vehicle newly travels on a different route in the same section as the existing section traveling route.
When the vehicle thus travels on a new route different from the existing section traveling route, the number of times the vehicle travels on the existing section traveling route is reduced, thereby making it possible to preferentially reflect the section traveling route which is high in the frequency of utilization in the guiding route.
Preferably, the route selecting system further comprises a return route selection portion receiving the current position found by the current position and traveling track detection portion and the guiding route generated by the guiding route generation portion, to examine whether the section traveling route including the current position and having a point crossing the guiding route in the travel direction exists in the section traveling route storage portion, and generating, when the section traveling route exists, a new guiding route from the current position to a destination point using the section traveling route and the guiding route. The map display output portion guides the user using the new guiding route generated by the return route selection portion when it is determined that the current position of the vehicle deviates from the guiding route.
When the current position thus deviates from the guiding route, the route to the destination point is newly generated on the basis of the route on which the vehicle once traveled, thereby making it possible to guide via a return route using the route on which the user has experience traveling. Accordingly, it is possible to enhance a user""s peace of mind.
Preferably, the section traveling route storage portion stores circumstances where the vehicle travels on the section traveling route together with the section traveling route, and the guiding route generation portion uses, for the replacement, only the crossing section traveling route whose circumstances stored in the section traveling route storage portion conform to the current circumstances.
The circumstances where the vehicle travels on the section traveling route and the section traveling route are thus stored together, and only the section traveling route conforming to the current circumstances is reflected in the guiding route, thereby making it possible to select the optimum route depending on the circumstances.
Preferably, the route selecting system further comprises a traveling track input portion for inputting a route (a traveling track) on a map on which a user desires to travel, the section traveling route generation portion using the traveling track inputted to the traveling track input portion in place of the traveling tracks found by the current position and traveling track detection portion, to extract the section traveling route.
Accordingly, the route (the traveling track) desired by the user is inputted, and the section traveling route in the section different from the optimum route is stored using the route, thereby making it possible to reflect the route conforming to the desire of the user in the guiding route even if the vehicle does not actually travel.
Preferably, the section traveling route storage portion individually stores the section traveling route for each user, and the crossing section examination portion and the guiding route generation portion each perform processing using only the section traveling route corresponding to the user. Consequently, it is possible to guide via an optimum route corresponding to an actual driver.
More preferably, the section traveling route storage portion determines the stored section traveling route in accordance with judgment given from the user. Consequently, it is possible to guide via a more optimum route in which the intention of the driver is reflected.
Typically, in a computer comprising a storage device (a ROM, a RAM, a hard disk, etc.) storing predetermined program data which can be executed and a CPU (Central Processing Unit) for executing the program data, the route selecting method described in the first aspect is realized. In this case, predetermined program data capable of executing each of the steps described in the first aspect may be introduced into the computer through a writable recording medium (a CD-ROM, a floppy disk, etc.).
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.